Quad flatpack-no lead (QFN) and small outline-no lead (SON) are leadless packages for integrated circuits (ICs) and micro-components, such as semiconductor and micro-electromechanical system (MEMS) devices. The packages have peripheral terminal pads, and an exposed die pad for mechanical and thermal integrity. As the terminals are essentially flush with the bottom surface of the package body, the packages are considered to be “leadless” or “no-lead.” A QFN/SON package may be used in a variety of applications, including applications requiring low standoff heights, improved thermal performance, reduced size or reduced weight. Cell phones, personal digital assistants (PDAs), portable music and video players can significantly benefit from QFN/SON packages.
Quad (QFN) versions of the package have terminals on all four sides of the bottom surface of the package. Dual Inline (SON) versions generally have terminals only on two opposite sides. The packages can be mounted, for example, on the bottom side of a printed circuit board (PCB). The small size of the packages better utilizes the available PCB area.
Additional details of small scale plastic QFN/SON packages may be found, for example, in the JEDEC Design standard, “Design Requirements for Outlines of Solid State and Related Products,” JEDEC Publication 95, Design Guide 4.2 (June 2005). As the QFN/SON packages according to the foregoing JEDEC design standard are plastic, the integrated circuit or other micro-components are not sealed hermetically within the package.